Recently purchased a used Aritsugu A-type to play with. Blade is very odd--the right side looking from the top is very concave outwards although it had been thinned somewhat. The left side is dead flat, as if the knife started life as a single beveled model that has mutated. I can get the edge sharp as hell, but the stiction to the flat side is very strong. I would think the flat side would need to be convexed to help this. I guess I am asking if that sounds right and is there a practical way to do that without power tools?

Dave Martell

09-23-2012, 11:22 PM

The A-type gyutos aren't single beveled but people make them this way by not following the geometry of the blade when sharpening. They come with an edge bevel on the back side that's buffed over but can be seen with a straight edge laid on the blade face. From a sharpening perspective, if the back side was worked the same as the front then the sticking issue would be a lot less of a problem.

To correct what you have on this knife then yes I'd advocate a convex, a large convex, on the back side. It should be a very shallow angle. Of course just raising the spine off of the stone while sharpening and putting the edge bevel back on the knife will help too but it's the geometry of the blade that needs correcting here.

pitonboy

09-23-2012, 11:39 PM

Dave, it this possible to do by hand in a practical sense?

Dave Martell

09-24-2012, 09:47 AM

Dave, it this possible to do by hand in a practical sense?

Well not in a practical sense, you'll probably hate this job, but it can be done. I'd approach it like I was working on a wide single hamaguri (convex) bevel, sort of like blended multi bevels. Yeah it'll be some tough grinding on this knife for sure.

Lefty

09-24-2012, 10:01 AM

Might as well give it to me, I guess. Sounds like junk! ;)

Actually, has anyone seen a lefty-favoured a-type, other than Brandon's?

Rottman

09-24-2012, 10:17 AM

Might as well give it to me, I guess. Sounds like junk! ;)

Actually, has anyone seen a lefty-favoured a-type, other than Brandon's?

Mine, gotta check if I find the choilshot from a few years back.

Lefty

09-24-2012, 10:19 AM

How attached to it are you, exactly? Haha

pitonboy

09-24-2012, 10:22 AM

Not attached emotionally; it is just a fixit project; maybe I am using it as an excuse to get a bench sander:biggrin:

How attached to it are you, exactly? Haha

Rottman

09-24-2012, 10:29 AM

Here's a choilshot of the 270 A-type, a Hiro AS 270 is on the left. A-type needs a new handle where the blade could be mounted a little anti-clockwise. I've convexed the left side more since taking the pic. http://i893.photobucket.com/albums/ac136/Rottman666/Aritsugu/HiromotoAS-Aritsugu.jpg